A. Ghasemi, Isfahan University of Technology, Isfahan, Iran

Summary: The sols were made from several acid catalysts including HNO3-HCL, CH3COOH, HCL, basic catalyst ( NH4OH, NH3 ) and two-step catalyst such as CH3COOH-NH3.To produce adherent silica coatings on nickel, various additives such as surfactant, viscouse additives and drying control chemical additives were introduced to the system, The results indicate that uniform coating of silica can be produced on nickel substrate by optimizing composition of the sol and the process variables .